Regulating system



Nov, 20, 1945. P; C JENKS v 2,389,364

REGULATING SYSTEM Filed Nov. 1, 1944 WITNESSES: INVENTOR m Harold C.Jenks.

ATTO R Patented Nov. 20, 1945 UNITED STATES PATENT OFFICE This inventionrelates to regulating systems supply represented by the positive andnegative and in particular to regulating systems formainterminalstaining balanced output betwe n parallel com In order tocontrol the energization of field nected generators. windings 32 of theexciter 30 and consequently Heretofore where alternating-currentgeneracontrol the excitation of the generator l0, a suittors have beenconnected in parallel fo supp1y able voltage regulator 36 is connectedto be re- 01 the individual exciter being controlled by a the pamcmartype of voltage regu' suitable voltage regulator as many reguator isrelatively unimportant and as many diflators have been required as thereare generator fel'ent es are well known it is within the scope Inaddition cross current compensating devices of this mventlon to utilizeany of the stand d have been p yed in conjunction with the voltvoltageregulatorsage regulators in an eilort to obtain a uniform with thevottage regulator 36 connected in the distribution of the load betweenthe generators. manner descnbed as the voltage across 34 in circuit withthe field windings 32, thereby parallel connefted generatorsof sectionsof the field rheostat 34 in circuit with r The generator l2 comprisesarmature windings the exc tation of the other generator belngcondisposed to be connected by conductors 42, trolled in response to thepower factors of the outand through the threemole Switch 43 to the loadconductors It, It and 20, respectively, and

35 trolling the excitation of the generator I2. An

Referring to the drawing, there is illustrated a 40 being connectedthrough an adjustable resistor 60 plurality of generators I0, l2 and I4disposed to across the field windings 50. The field windings beconnected to load conductors l6, l8 and 20 for 56 of exciter 52 areconnected through an adv parallel operation for supplying a load (notjustable resistor 62 across a pilot exciter (not ture windings 22connected directly to the load 4 cated by the positive and negativeterminals and,

connected to be energized to control the excitastant source of supply asthe field windings 32 of tion and consequently the output of thegenerator the exciter 30. In. The field winding 24 of generator I0 iscon- In Order to Control h ene gization of the field nected through anadjustable resistor 26 across 5 windings 58 of exciter 52, the windings58 are the armature windings 28 of an exciter 30. disposed to beconnected through an electric As illustrated, the exciter 30 is providedwith valve dis ha e device 64 to the secondary ndfield windings 32disposed to be connected through ings 66 of a transformer 68. Thetransformer a field rheostat 34 to a pilot exciter (not shown) 68 isalso provided with other secondar windor any other suitable constantsource of power, ings 10 and primary windings 12, the p im y v windings58 of windings being connected across conductors 42 and 48 supplied bythe generator I2,

The electric valve 84 comprises an anode 14, a screen grid 18, a and acathode 82. The electric valve 84 has the characteristics that whencurrent voltage, if rendered conducting impulse, it will conduct currenting portion of the positive half-cycle of the voltt will be renderednon-conducting to the arc drop value nd will not be re-establishedduring the negative half-cycle of that voltage wave.

As illustrated, the secondary windings 86 of transformer 88 forsupplying current to the field the exciter 52 have one of theirconnected to the anode 14 of valve 84, the secondary windings 88 thefield windings 58 84 to the cathode 82 of electric The flow of currentthrough the field windings so that terminals the other d In order toprovide a negative bias on the grid 18 of electric valve 84, thesecondary windings 10 of the transformer 88 are connected across theinput terminals of a rectifying bridge circuit 88, one of the outputterminals of which is connectis provided for I04 of the to a current ininductive relation with the conductor 44 from the generator I2.

is of a type well known'to the industry, the leg of the magnetic coreupon which the secondary windings 88 are wound being so designed that itwill saturate very early in the current cycle an as a result of a peakedimpulse of considerable magnitude.

the valve 84 is normally mainconducting by the negative bias appliedtained thereto, whenthe presses its peaked voltage on the grid circuit,the grid 18 is rendered the critical grid and render the valveconductive. The phase position of the impulse impressed on the gridcircuit by the impulse transformer 80 will be dependent upon 'current ofthe output of the generator I2. Thus, unity power factor, peak of thewave, whereas for a impulse comes at an earlier time in the positivehalf-cycle of the voltage wave power factor the impulse comes later in tpositive half-cycle of the voltage wave. Thus with the field windings 58connected across the anode 14 and the cathode 82 of electric valve 84,it is apparent that the current flowing 58 is dependent upon the valve84, the conductivity of which is controlled through the impulsetransformer 80 in the rapid saturation will provide 84 by the power l ina balanced relation withv respect res onse to the power factor of theoutput of generator I 2.

With the circu't as just described, it is apparent that when 84 isconducting the windings 58 are energized to so excite the exciter 54 asto increase the output thereof and so inexcitation of the generator I2that its power factor tends to shift toward a lag in power factor. Inorder to limit the operation of the valve 84 so as to control the powerfactor of the output of the generator I2 and maintain it I0,anotherelectric valve I08 is disposed to control the bias of the grid 1electric valve 84 in response to the power factor of the output ofgenerator III. The valve I08 is generator anode IIO,

a screen grid H2, a biasing H8 and a cathode I I8. I

In order to provide a negative bias for the grid II4 of valve I08, atransformer I20 having secondary windings I22 and I24 and primary windings I28 is provided, the primary windings I28 conductors the loadcircuit. As illustrated, the secondary windings I22 of the transformerI20 are connected across the input terminals of a rectifying bridgecircuit I28, one of the output terminals of which is connected throughthe secondary windings I of an impulse transformer I32 and a resistorI34 to the grid II4, the other terminal of the rectifying bridge circuitI28 being connected by conductors I36 and I38 to the cathode II8 of thevalve I08. v The impulse transformer I32 is similar to the impulsetransformer 80 having primary windings I40 connected across a currenttransformer I42 disposed in inductive relation with respect to loadconductor I8, whereby the transformer impresses an impulse on the gridbiasing circuit in response to the power factor of the current in theload conductors. The function of the impulse transformer I32 is the sameas that of impulse thus apparent is dependent upon of generator I0 andthe load conductors and 20.

The .anode IIO of the valve I08 is connected by conductor I44 to aterminal of the secondary windings I24 of transformer I20, the otherterminal of secondary windings I24 being connected by conductor I48through resistor 98 and conductor I48 to the cathode II8 of the valveI08. Thus the output of the valve I08 impresses a voltage on the gridbiasing circuit of valve 84 by reason of the interconnected resistor 88which is additive to the normal negative bias to definitely render thebias on the grid 18 negative. The negative bias impressed on the gridcircuit of the valve 84 is thus directly dependent upon the power factorof the output of the generator I0 whereby the firing of the valve 84 isdetermined by =the power factor of the outputs of generators I0 and I2.

Because of the characteristics of the valves 84 and I08, if valve 84 isrendered conductive by the action of the impulse transformer 88 inresponse to the power factor of the output of the generator I2 beforevalve I08 is rendered conducting, the valve 84 will remain conductivefor the remaining portion of the positive half-cycle of the voltage waveand the firing of the valve I08 will have no effect on thevalve 84.However,

I8 and 20 of 60 and 62 connected if by reason of the power factor of theoutput of the generator I or by reason of a change in the power factorof the output of generator I2, the impulse from the impulse transformer90 should come later in the voltage wave than the impulse from thetransformer. I82, then the negative bias impressed on the grid circuitof valve 64 by reason of the valve I06 being rendered conductive, issufficient to maintain the valve 64 non-conducting whereby currentceases to fiow in the field windings 58. Under such conditions, theexcitation of the exciter 52 is dependent upon the energization of thefield windings 56 with the result that the output of the exciter 52 isreduced to lower the excitation of the generator I2 and cause the powerfactor of the output of generator I2 to tend to be more leading.

The generator I4 is similar to the generator I2 having its armaturewindings I50 connected by the three-pole switch- I52 to load conductorsI6, I8 and 20, the field windings I54 of the generator I50 beingdisposed to be energized by the output of an exciter I56. The exciterI56 is provided with field windings I56 and I60 which correspond to thefield windings 56 and 58 of exciter 52.

The fiow of current through the field windings I60 is controlled by avalve I62 connected in circuit relation with a transformer I64. Thevalve I62 is identical to valves 84 and I06 and has the samecharacteristics, being provided with an anode I56, a biasing grid I66and a cathode I10.

In order to control the negative bias on the grid I68, a rectifyingbridge circuit I12 is connected to one of the secondary windings of thetransformer I64 and has one of its output terminals connected throughthe secondary winding of an impulse transformer I14 through a resistorI16 to the grid I66, the other terminal being connected by conductorsI18 and 86 through a part of the resistor and conductors I 00 and I60 tothe cathode I10.

Thus since the field windings I60 of the exciter I56 are connectedacross the anode I66 and the cathode I of the valve I62, the currentfiow through the field windings I60 is dependent upon the cooperativefiring of the valves I62 and I06 in the same manner as the cooperativefiring of the valves 64 and I06 for controlling the flow of currentthrough the field winding 58 of exciter '52. In both cases, the resistor96 functions when the valve I08 is conducting to impress a negative biason the grid circuit of the valves associated with generators I2 and I4to render the valves 64 and I62, respectively, non-conducting when thevalve I08 is rendered conductin ahead of the valves 64 and I62.

In operation, where it is desired to maintain a balanced output betweenthe generators I0, I2 and I4, the output of the generator I0 is firstadjusted to a desired value and by reason of the operation of theautomatic voltage regulator 36, the output of generator I0 is maintainedsubstantially constant. When the voltage of the generator I2 is broughtup to the predetermined voltage of the generator I0 by adjustingresistors in the field circuits of the exciter 52 and the generator I2,respectively, the switch 48 is actuated to a circuit closing position toconnect the generator I2 in parallel with the generator I0. Similarly,generator I4 is connected in parallel with the generator I0 after the I4has been adjusted by the field circuits of the Under these voltage onthe generator adjusting the resistors in exciter I56 and the generatorI4.

3 conditions, each of the generators I0, I2 and I4 are operating in abalanced relation as a result of the manual adjustment of the resistors.

In order that the regulating system of this invention may functionautomatically to maintain the output of the generators I2 and I4balanced with respect to that of the generator I0, the resistor 62 incircuit with the field winding 56 of the exciter 52 is manually adjustedto decrease the fiow of current therein to a value below that value atwhich the regulating systems begin to function to energize the fieldwindings 68 of the exciter 52 to control the power factor of the outputof the generator I2. Similar adjustments are made in the resistor inthe'field circuit of the exciter I56 of generator I4 until theregulating system functions to control the energization of the fieldwinding I to control the output of the exciter I 56 and consequently theexcitation of the generator I4.

Assuming that the generator I0 is so regulated that its output is atunity power factor and that the generators I2 and I4 are connected inparallel with the generator I0 as previously described, if for anyreason the power factor of the generator I2 should tend toward a leadingvalue away from the balanced Dower factor at unity value, then theimpulse transformer 60 functions to impress a peaked voltage on the gridcircuit of the valve 64 to render the valve 64 conducting. When thevalve 64 is rendered conducting, current fiows through the circuitextending from the anode 14 through the secondary winding 66 oftransformer 68, field winding 58 and conductor 84 to the cathode 82 ofthe valve 64 to so energize the field windings 58 that the output of theexciter 52 is increased to effect an increase in the excitation of thegenerator I2 and cause its power factor to shift to a less leading or toa lagging value.

When the power factor of the output of generator I2 is thus shiftedbeyond unity power factor to a lagging value, the valve I08 functions toprevent further operation of the valve 64 for forcing the excitation ofthe generator I2. This is because with the power factor of the output ofgenerator III at unity value, the impulse transformer I32 impresses apeaked voltage on the grid circuit of valve I08 at a point on thepositive half-cycle of the voltage wave represented by unity powerfactor So that the valve I06 becomes conducting at that point. When thevalve I06 is rendered conducting, current flows in the circuit whichextends from the anode IIO through conductor I 44, secondary windingsI24 of transformer I20, conductor I46, resistor 96 and conductor I48 tothe cathode II8 of the valve I06. The fiow of current through theresistor 98 impresses a potential on the grid circuit of the valve 64which is additive to the normal negative bias thereof, whereby the grid16 of valve 64 is positively rendered negative to prevent the valve 64from conducting.

By thus deenergizing the field windings 58, only the field windings 56of the exciter 52 function to energize the exciter '52 whereby theoutput of the exciter 52 is so decreased as to decrease the excitationof the generator I2 as to cause its power factor to shift to a moreleadingvalue. As will be apparent, the cooperative firing of the valves64 and I08 will maintain the power factor of the output of generator I2balanced with re- -spect to the power factor of the output of generatorI6.

The enerator I4 will be controlled in a mantrative that the output ofmore apparent that only ner identical to that of generator 12, theoperation of the regulating systems being identical in that the valvesI62 and I08 cooperate in the manner described with respect to valves 64and I08 whereby the excitation of the exciter I56 is so controlled as tocontrol the excitation of the generator M to maintain the power factorof the output of generator i4 balanced with respect to the output ofgenerator 10. It is believed that further description of the operationof the system with respect to generator 14 is unnecessary, referencehaving been made to generator M as illusthan two generators can bemaintained in a balanced condition by the regulating system of thisinvention By utilizing the system of this invention, it is one automaticvoltage regulator is necessary regardless of the number of generatorsconnected in parallel and that the appaiatus necessary for paralleloperation of the generators is thus greatly si plified. The regulatingsystem of this invention automatically provides cross currentcompensation and as the apparatus employed is of standard construction,the systems can readily be duplicated. After the generators have oncebeen connected in their parallel relation, little maintenance isrequired as the systern automatically corrects for any tendency to varyfrom an unbalanced condition.

While this invention has been described with reference to a particularembodiment thereof, it is, of course, to be understood that it is not tobe limited thereto except insofar as is necessitated by the scope of theappended claims.

I claim as my invention:

1. A system for regulating the operation of parallel connectedalternating-current generators, comprising, in combination, an exciterdisposed for operation to control the excitation of a first one of thegenerators, an automatic voltage regulator responsive to the voltageacross the firstnamed generator for controlling the operation of theexciter, a second exciter disposed for operatlon to control theexcitation of a second one of the generators, the second exciter havinga pair of field windings, means for controlling the energization of oneof the field windings for controlling the initial excitation of thesecond-named generator. means responsive to the power factor of thesecond-named generator disposed to control the energization of the otherfield windin of the second exciter, and means responsive to the powerfactor of the first-named generator disposed to cooperate with the powerfactor responsive means of the second-named generator to limit thefunctioning thereof whereby the excitation of the second-named generatoris controlled to maintain balanced output between the generators.

2. A system for regulating the operation of parallel connectedalternating-current generators, comprising, in combination, an exciterdisposed for operation to control the excitation of a first one of thegenerators, an automatic voltage regulator responsive to the voltageacross the first-named generator for controlling the operation oftheexciter, a second'exciter disposed for operation to control theexcitation of a second one of the generators, the second exciter havinga pair of field windings, means for controlling the energization of oneof the field windings for controlling the initial excitation of thesecond-named generator, means including an electric valve disposed toconnect the other field winding of the second exciter to be energized,the electric valve negative bias having a grid to be utilized forcontrolling the conductivity thereof, a grid circuit responsive to thepower factor of the second-named generator for controlling the bias ofthe grid to control the energization of the other field winding, andmeans responsive to the power factor of'the first-named generatordisposed to cooperate in the grid biasing circuit of the electric valveto maintain the valve non-conducting under predetermined operatingcondition whereby the excitation of the second-named generator iscontrolled to maintain balanced output between the generators.

3. A system for regulating the operation of parallel connectedalternating-current generators, comprising, in combination, an exciterdisposed for operation to control the excitation of a first one of thegenerators, an automatic voltage regulator responsive to the voltageacross the firstnamed generator for controlling the operation of theexciter, a second exciter disposed for operation to control theexcitation of a second one of the generators, the second exciter havinga pair of field windings, means for controlling the energization of oneof the field windings for controlling the initial excitation of thesecond-named generator, means including an electric valve dis posed toconnect the other field winding of the second exciter to a source ofpower, the electric valve having a grid to be utilized for controllingthe conductivity thereof, means for applying a to the grid, means forrendering the grid positive in response to the phase angle of thesecond-named generator to control the energization of the other'winding,the positive biasing means including an impulse transformer connected tobe responsive to the flow of current from the second-named generator,and means responsive to the power factor of the first-named generatordisposed to cooperate in the grid biasing circuit of the electric valveto maintain the valve non-conducting under predetermined operatingconditions whereby the excitation of the second-named generator iscontrolled to maintain balanced output between the generators.

4. A system for regulating the operation of parallel connectedalternating-current generators, comprising, in combination, an exciterdisposed for operation to control the excitation of a first one of thegenerators, an automatic voltage regulator responsive to the voltageacross the firstnamed generator for controlling the operation of theexciter, a second exciter disposed for operation to control theexcitation of a second one of the generators, the second exciter havinga pair of field windings, means for controlling the energization of oneof the field windings for controlling the initial excitation of thesecond-named generator, means including an electric valve disposed toconnect the other field winding of the second exciter to be energized,the electric valve having a grid to be utilized for controlling theconductivity thereof, a grid circuit responsive to the power factor ofthe second-named generator for controlling the bias of the grid tocontrol the energization of the other field winding, a second electricvalve connected to impress a negative bias on the grid of thefirst-named valve to render the first-named valve non-conducting whenthe second-named valve is rendered conducting ahead of the first-namedvalve, the second-named valve being responsive to the power factor ofthe firstnamed generator to control the negative bias impressed by thesecond-named valve on the grid of the first-named valve whereby thevalves cooperate to control the excitation of the secondnamed generatorto maintain balanced output between the parallel connected generators.

5. A system for regulating the operation of parallel connectedalternating-current generators, comprising, in combination, an exciterdisposed for operation to control the excitation 01' a first one of thegenerators, an automatic voltage regv ulator responsive to the voltageacross the firstnamed generator for controlling the operation of theexciter, a second exciter disposed for operation to control theexcitation of a second one of the generators, the second exciter havinga pair of field windings disposed to be additive in their eil'ect whenenergized, one of the field windings being connected to a constantsource of power supply, an adjustable resistor connected in circuitrelation with the one field windingior initially controlling theexcitation of the second exciter, and an electric valve circuitconnected to be responsive to the power factor 01' each of thegenerators for automatically controlling the energization of the otherfield winding 01' the second exciter and thereby control the excitationof the second-named generator to maintain balanced output between theparallel connected generators.

6. A system for regulating the operation 01' parallel connectedalternating-current generators. comprising, in combination,

for operation to control the excitation of a first one of thegenerators, an automatic voltage regulator responsive to the voltageacross the firstnarned generator for controlling the operation of theexciter, a second exciter disposed for operation to control theexcitation of a second one of the generators, the second exciter havinga pair of field windings disposed to be additive in their eifect whenenergized, one 01 the field windings being connected to a constantsource of power supply, an adjustable resistor connected in circuitrelation with the one field winding for initially controlling theexcitation of the second exclter, a plurality of electric valves havinggrids for controlling the energization of the other field winding of thesecond exciter, a first one 01' the valves being disposed to connect theother field winding to a source of power, a grid circuit responsive tothe power factor of the second-named generator for controlling the biason the grid 0! the firstnamed valve to render the first-named valveconducting, the second one oi' the valves having a grid biasing circuitresponsive to the power factor of the first-named generator to controlthe output of the second-named valve, and means interconnecting theoutput 01' the second-named valve with the grid biasing circuit of thefirstnamed valve whereby the second-named valve impresses a negativebias on the grid 01' the firstnamed valve to render it non-conductingwhen the second-named valve is rendered conducting ahead of thefirst-named valve, the electric valve thereby cooperating to control theexcitation of the second-named generator to maintain balanced outputbetween the generators.

HAROLD C. JENKB.

